Tire Pressures - Do you run factory recommended?

[joel-cs]

Just bought a 2004 2500HD 8.1/Allison. Working great so far, but I noticed something that still has me scratching my head - On the driver's door, recommended pressures are 60 front and 80 rear. Coming from cars and SUV's (wife has a Suburban), this sounds extremely high to me.

Is this the pressure you run at? I did inflate to these pressures and it improved the ride significantly from before (the dealer had them at 32/32!), but I don't want to overinflate... Does it change for towing (I tow a 6,000# car hauler).

Thanks.

[cabletech]

Those are for max load. I run 55 front and 50 rear when driving my truck unloaded and 65 front and 70 rear when pulling my 5th wheel.

Jay

[EdHale]

My Suburban diesel required 55psi in both front and rear in order for the tires to wear evenly across the tread. This number was arrived at over 245,000 miles and several sets of tires. Since my new 2006 Sierra weighs similar, I would expect a similar number would be required. I presently keep 60psi in both front and rear unloaded. When I load it up, I do increse the rear to 80.

[More Power]

I run 75 in the front, then match the tire bulge in the rear using whatever psi is required. If running solo, the rears get about 50-60 psi, more if loaded heavy.

If you rotate your tires frequently, you may not see the typical front tire shoulder wear and you may not see the rear tire centers wear. I usually don't rotate till I see the pattern develop.

The idea is to get the tires to wear flat across the tread, but I've yet see it.... Adjusting tire pressures help. Rotating helps....

Jim

[EdHale]

I do rotate religiously every 5-6000 miles, so a pattern may not show up for me. The last set of Michelins I had on my suburban lasted 97,000 miles and still have a few thousand left.

[rob from bc canada]

I always figured the only reason to run pressure lower than maximum factory reccommended would be to improve the ride, and since I figure my ride is pretty good already...

Good reason to run pressure on high side is improved mileage due to reduced rolling resistance.

True - if your pressure is a bit on the high side, you might get a bit of centre-wear on the rears, but the tire life would likely be longer due to reduced heat build-up.

Periodically rotating front to rear should even out the edge and centre wear quite nicely.

[SoTxPollock]

If you run 80 psi in the rears unloaded, you are definately going to wear out the centers. DmaxMaverick has the right idea. Look at it this way, the more bulge you see when the tire is sitting still the more heat from internal friction will be generated because you are bending those steel belts and the rubber in the tire everytime that particular part of the tire comes in contact with the road surface, that is why I run at least 70 in the fronts and match the rears to look like the fronts, just a small amount of bulge.
Of course if you run 80 you won't see a bulge unless you are pretty heavely loaded. IMHO GM recommending 55 in the front is to make it as soft a ride as possible, but remember you are the one paying for the new tires not GM.

[rob from bc canada]

I will have to admit, I was exaggerating slightly.

I checked today, and I've been running 65 in the front and rear unloaded.

Now that I stuck the Camper back on, I bumped the rears to 75.

[mark45678]

60~65 in the front of my crewcab 4x4 and 50~70 in the rear depending on load.

[letsgo]

Your geting mixed measages, which is quite reasonable considering that most drivers have different tire sizes.
my pressures are 70psi front 65psi rear (carry 76gals of fuel), and 75psi front 80psi rear (when towing).

the way I decided was to watch tire wear starting at 65psi front and 50psi rear, run your hand over the top part of the tire fealing the tread edges, if the edges are sharp instead of rounded then the tire is being torn or shreaded, increase the preasure 5psi all round.

If the shreading continues you have a wheel aligement problem, and when I tow, tire rotation once a year or every 10,000mi is important for good wear.

drive safe
good luck